Obstructive sleep apnea is a condition where breathing repeatedly gets interrupted during sleep which leads to frequent arousals and reduced oxygenation during the night and excessive sleepiness during the day. This happens due to obstruction in the upper airway, which can be dynamic during sleep. It can lead to a multitude of medical problems like hypertension, heart failure, heart attacks (coronary artery disease), and brain attacks (strokes-both ischemic and hemorrhagic). The prevalence of Obstructive sleep apnea in India ranges from 5% to 14%, higher prevalence observed in men than in women.

Stroke is the second leading cause of death and a major cause of disability worldwide. India accounts for 10% of the global stroke burden. In India, a stroke occurs every 30 seconds and a death every 3 minutes. There has been an alarming rise of stroke cases in India-more so young strokes, over the past 2 decades.

Around 50–70% of people who experience a stroke also suffer from some form of sleep apnea (mild to severe). With today’s sedentary lifestyle, obesity, metabolic syndrome-related factors, the prevalence of Obstructive Sleep Apnea (OSA) has increased significantly. OSA is now recognised as one of the major risk factors for recurrent strokes.

Often, people are aware of common stroke risk factors such as diabetes, hypertension, and high cholesterol. However, sleep apnea is rarely recognised as one, sometimes even by treating physicians. Individuals with diabetes or hypertension who are on blood-thinning medications may still experience repeated strokes if their underlying sleep apnea remains undiagnosed and untreated. If OSA remains untreated in patients who have had a stroke, there is a 50% chance of recurrence within two years.

How can sleep apnea be diagnosed?

Sleep apnea is measured using the Apnea-Hypopnea Index (AHI), which is obtained through a sleep study. A simple sleep test monitors sleep patterns to determine the severity of apnea.

For mild cases of OSA (AHI 5-15), lifestyle modifications such as regular exercise and weight reduction can be very effective. 

When the AHI is above 15, patients are generally advised to use a CPAP (Continuous Positive Airway Pressure) machine, a device with a mask worn over the nose during sleep that helps maintain constant and steady air pressure during sleep

Apart from CPAP usage, sometimes, correction of the obstruction via surgery (uvulopalatopharyngoplasty, nasal and palatal correction surgeries, when indicated) can be an effective long-term solution for managing OSA.

Hence, it is important to look for this cause in every patient of stroke, more so for those lacunar (small, deep territory) strokes within the brain. Apart from looking for causes of other rarer causes of stroke recurrence, this will be a significant step towards preventing stroke recurrence